Integrated insulation extrusion and extrusion technology for window and door systems

ABSTRACT

Extruded plastic profiles with integrated insulation, the method for extruding such products, and the windows and doors made with such plastic extrusions. The plastic extrusions may additionally include a low heat build-up capstock system comprising an acrylic cap and pigment system that is substantially IR transparent. The extruded plastic profiles with integrated insulation are recyclable using conventional plastic extrusion process and are fully weldable in conventional window and door manufacturing.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a divisional application claiming priority topending U.S. patent application Ser. No. 12/592,277 filed Nov. 21, 2009;the disclosures of which are incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Technical Field

The invention concerns extruded plastic profiles with integratedinsulation and the method and apparatus for extruding such products.

2. Background Information

Milled wood products have formed the foundation for the fenestration,decking, venetian blinds, shutters, decking and remodeling industriesfor many years. Historically, ponderosa pine, fir, red wood, cedar andother coniferous varieties of soft woods have been employed with respectto the manufacture of residential window frames, residential doorframes, residential siding, outer decking and exterior shutters as wellas interior venetian blinds and shutters. Wood products of this typeinherently possess the advantageous characteristics of high flexuralmodulus, good screw retention, easy workability (e.g., milling,cutting), easy paintability, and for many years, low cost. Conversely,wood products of this type have also suffered from poor weatherabilityin harsh climates, potential insect infestation such as by termites, andhigh thermal conductivity. In addition, virgin wood resources havebecome scarce causing correspondingly high material costs.

Alternatively, various metals, especially extruded aluminum, have beenused and continue to be used as residential window and door frames inaddition to commercial window and door frames. Metal products of thistype inherently possess the advantageous characteristics of highflexural modulus and easy paintability, but also suffer from highthermal conductivity.

The high thermal conductivity of both milled wood products and extrudedaluminum have become particularly disadvantageous for the window anddoor products of the fenestration industry. Due to increasing energycosts and increased awareness and concern over energy usage inresidential housing, there is governmental regulatory pressure frombuilding codes, product certification requirements, incentive programssubsidizing the purchase of thermally efficient residential housingwindows and door products, and general market demand for ever morethermally efficient windows and door products.

In response to the above described disadvantages of milled wood productsand metal products, the fenestration industry, in particular, adoptedpolyvinyl chloride (PVC) as a raw material. Hollow, lineal extrusionsmanufactured into window frames became an enormous success, particularlyat the lower end of the price spectrum. The window frames and sashesmade from hollow PVC lineals (often referred to as “vinyl windows”) haveexhibited superior thermal conductivity compared to painted ponderosapine window or extruded aluminum. Further, foamed polymer solidextrusions have been used to replace wood window frames and sashes. Thefoamed polymer extrusions may contain organic or inorganic fillers, suchas wood flour and talc, respectively, where advantageous for improvedphysical properties such as stiffness and/or to reduce the cost of theextrusions.

Due to the high thermal conductivity of extruded aluminum window anddoor frames, and even to further improve the thermal performance ofvinyl windows and doors formed from hollow PVC lineals, the fenestrationindustry has inserted foam insulation into the hollow interior portionsof the extrusions. This insulation can significantly improve the thermalperformance of a window or door frame, and therefore improve the thermalperformance of the entire window, by reducing the free air within aninterior pocket or chamber of the hollow extrusion. This free air withina chamber of the extrusion can cause significant heat transfer throughthe walls of the extrusion due to the temperature difference between theinside and outside walls of the extrusion causing the air to cyclearound in the cavity causing convective heat loss in the associatedwindow. The insulation within hollow can reduce or eliminate thisconvection heat transfer. The determination of which pocket or chamberwithin the window or door frame extrusion would see the most benefitfrom such insulation is dependent on the particular shape of the windowextrusion and window and is determined on a case-by-case basis based onthermal simulations or sample testing.

One commonly used prior art foam insulation is a low density blockpolystyrene based foam, often referred to as Styrofoam, which is cut orotherwise dimensioned to fit within the desired pocket or chamber withinthe window or door frame extrusion. Such a polystyrene block willinsulate well should it substantially fill the chamber, but achievingthis proper fit is the significant disadvantage. Rarely are the pocketsor chambers within the window or door frame extrusion a standard orregular size, so that usually the polystyrene will have to be cut downfrom a block or sheet causing scraps and wasted insulation. Insertingthe polystyrene insulation into the pocket or chamber within the windowor door frame extrusion can be difficult if the clearance between theexterior of the polystyrene insulation and the chamber are too tight,but too large air gaps between insulation and extrusion will diminishthe thermal performance. Thus, this can be a significantly laborintensive and costly process.

A second prior art foam insulation is a low density, CFC free,semi-rigid polyurethane foam. This is typically an in-place foam processthat uses equipment to mix two ingredients together where this mixtureis then injected and expands within the chamber to be insulated. Anexample of this prior art foam insulation is FOAMSEAL® P12844/FSA soldby Futura Coatings of St. Louis, Mo. This process is another processstep for a window or door manufacturer which adds labor costs. Further,both the polystyrene foam and the polyurethane foam are separatematerials from either the extruded aluminum or the PVC lineals that makeup the window frames making it more difficult to recycle the basematerials.

As above, an advantage of windows manufactured with wooden frames andsashes is that they can easily be stained or painted virtually anycolor. Thus, the color of the window frame and sash could be chosen toaccent or contrast with the color of the exterior of the house. Theprior art PVC products are typically available only in white or beige orother colors that do not readily absorb in the IR spectrum and thereforedo not build up sufficient heat to distort the body of the extrusion.Typically, these mono-color extrusions are seen in lighter shades andpastels where heat build-up is not a problem and where the requiredamount of pigments does not unduly increase the cost of the extrusion.

Understandably, window and door profiles in dark colors, such as “HunterGreen” and “Bronze,” have long been demanded in the industry andavailable in wood or extruded aluminum which has been a significantmarket advantage of such products. When referring to dark colors herein,the inventor is referring generally to colors with an Lh value between13 and 40. For example, per ASTM 4726-02, dark brown is defined as acolor with an Lh between 13 and 33, an ah between −1.0 and 6.0 and a bhbetween 1.0 and 6.5. Per AAMA 308-02, dark green is defined as a colorwith an Lh between 20 and 40, and ah between −20 and −2 and a bh between−2.0 and 4.0. The inventor defines the color red to have Lh valuesbetween 20 and 30, ah values between 13 and 23, and bh values between 6and 12.

Applying a thin capstock layer to hollow vinyl profiles and solid foamedpolymer resin extrusions is well known in the art. Typically, thecapstock layer is applied for the purpose of achieving color,weatherability, and certain appearance attributes in a cost-effectivemanner. Frequently, this allows the practitioner to use a lower-costmaterial in the substrate and therefore reduces total product cost.However, in the past, the useful color spectrum that can be applied toPVC hollow or foamed profile extrusion is limited to colors and pigmentsystems that do not build up excessive heat and thereby cause the bodyof the product to distort.

Assignee of this application has been assigned co-pending U.S. patentapplication Ser. No. 11/291,494 entitled “Low Heat Build-up CapstockSystem and Extrusion Technology for Solid and Foamed Profiles in DarkColors” which allows the production of a dark colored capstock that issignificantly NIR transparent rather than NIR reflective, and relies onan NIR reflective substrate for the NIR reflectance and allows a darkcolored capstock on hollow PVC extrusion. Disclosure of that applicationis incorporated herein by reference.

SUMMARY OF THE INVENTION

It is therefore an object of the invention to provide an extrudate withintegral foam insulation. This inventive extrudate comprises astructural extrusion formed of a first thermoplastic resin suitable foruse in the fenestration industry, contains at least one hollow interiorportion and has a constant profile and extends to an indefinite length.An integrated insulation formed of a second thermoplastic resinsubstantially fills a hollow portion of the structural extrusion and, ina preferred embodiment, this integrated insulation is foamed and formedso that this foam further contains a plurality of air pockets running inthe length of the extrudate. The first thermoplastic resin and thesecond thermoplastic resin are compatible and recyclable together andthe structural extrusion and the integrated insulation are coextrudedthrough an extrusion die to form the inventive extrudate. It is afurther preferred embodiment to further include a dark-colored capstockof a third thermoplastic resin that is significantly transmissive ofsolar infrared radiation and that covers at least a portion of thestructural extrusion, where the dark-colored capstock is less than about10 thousandths of an inch thick. An alternate embodiment includes afourth thermoplastic resin to make up portions of the structuralextrusion, which can be produced with a lower cost thermoplastic resinfeedstock.

It is a further object of the invention to provide a window for use in aresidential or commercial structure comprising a glass pack operativelyinstalled in a window frame, where the window frame further comprisesthe inventive extrudate and its embodiments described in the paragraphabove.

It is a still further object of the invention to provide a method ofproducing the extrudate with integral foam insulation described inparagraph above, comprising feeding a first thermoplastic resin suitablefor use in a structural component in the fenestration industry into afirst extruder, feeding a second thermoplastic resin suitable forintegrated insulation into a second extruder, outputting the first andsecond extruders to an extrusion die extruding the extrudate, where theextrusion die forms the structural extrusion formed of the firstthermoplastic resin, suitable for use in the fenestration industry,containing at least one hollow interior portion, of a constant profile,and extending to an indefinite length, and substantially fills thehollow portion of the structural extrusion with an integrated insulationformed of the second thermoplastic resin. In a preferred embodiment, thesecond thermoplastic resin of the integrated insulation is foamed andshaped to further contain a plurality of air pockets running in thelength of the inventive extrudate. In a still further preferredembodiment, the method comprises feeding a third thermoplastic resinthat is significantly transmissive of solar infrared radiation into athird extruder and outputting the third extruder into the extrusion dieso that the third thermoplastic resin forms a dark-colored capstocklayer of less than about 10 thousandths of an inch thick on a surface ofthe structural extrusion formed of the first thermoplastic resin.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plan view of an extrusion line of a type used with theinventive method.

FIG. 2 is an exploded view of downstream side of a multi-plate extrusiondie for use in a preferred embodiment of the inventive method.

FIG. 3 is a view of the flow of the various thermoplastic resin feedstocks in one of the plates of the multi-plate extrusion die shown inFIG. 2.

FIG. 4 is a view the flow of the various feed stocks in one of theplates of the multi-plate extrusion die shown in FIG. 2.

FIG. 5 is a view of the flow of the various feed stocks in one of theplates of the multi-plate extrusion die shown in FIG. 2.

FIG. 6 is a view the flow of the various feed stocks in one of theplates of the multi-plate extrusion die shown in FIG. 2.

FIG. 7 is a cut-away view of a two possible die orifices for use in oneof the plates of the multi-plate extrusion die shown in FIG. 2.

FIG. 8. is a view of the inventive extrusions showing profiles showingalternate embodiments of the integrated insulation.

FIG. 9 are top right perspective views, which are broken in the centerindicating indefinite length, of an example of the preferred embodimentof the inventive extrusion, showing the extrusion with and without theinventive integrated insulation.

FIG. 10 are top right perspective views, which are broken in the centerindicating indefinite length, of another example of a preferredembodiment of the inventive extrusion showing the inventive extrusionwith and without the inventive integrated insulation.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The inventive extrudate comprises a structural extrusion formed of afirst thermoplastic resin suitable for use in the fenestration industryand contains at least one hollow interior portion, has a constantprofile, and extends to an indefinite length. An integrated insulationformed of a second thermoplastic resin substantially fills the hollowportion of the structural extrusion and in a preferred embodiment thisintegrated insulation is foamed and this foam further contains aplurality of air pockets running in the length of the extrudate. Thefirst thermoplastic resin and the second thermoplastic resin arecompatible and recyclable together and the structural extrusion and theintegrated insulation are coextruded through an extrusion die to formthe inventive extrudate. It is a further preferred embodiment to furtherinclude a dark-colored capstock of a third thermoplastic resin that issignificantly transmissive of solar infrared radiation and that coversat least a portion of the structural extrusion, where the dark-coloredcapstock is less than about 10 thousandths of an inch thick and morepreferably between 4 and 8 thousandths of an inch thick. An alternateembodiment includes a fourth thermoplastic resin to make up portions ofthe structural extrusion.

The method of producing the extrudate with integral insulation describedin paragraph above, requires the use of a plastics extrusion line andcomprises feeding a first thermoplastic resin suitable for use in astructural component in the fenestration industry into a first extruder,feeding a second thermoplastic resin suitable for integrated insulationinto a second extruder, outputting the first and second extruders to anextrusion die extruding the extrudate. This extrusion die forms astructural extrusion formed of the first thermoplastic resin, suitablefor use in the fenestration industry, containing at least one hollowinterior portion, of a constant profile, and extending to an indefinitelength, and substantially fills a hollow portion of the structuralextrusion with an integrated insulation formed of a second thermoplasticresin. In a preferred embodiment, the second thermoplastic resin of theintegrated insulation is foamed and shaped to further contain aplurality of air pockets running in the length of the inventiveextrudate. In a still further preferred embodiment, the method comprisesfeeding a third thermoplastic resin that is significantly transmissiveof solar infrared radiation into a third extruder and outputting thethird extruder into the extrusion die so that the third thermoplasticresin forms a dark-colored capstock layer of less than about 10thousandths of an inch thick and more preferably between 4 and 8thousandths of an inch thick on a surface of the structural extrusion. Afurther alternate embodiment may include a fourth thermoplastic resinoutput by a fourth extruder to make up portions of the structuralextrusion, such as portions of the structural extrusion that are notsubject to the elements, or portions of the structural extrusion thatwould not typically be visible when the inventive extrusion has beenmanufactured into a window for use in a residential or commercialstructure. In such a case, the fourth thermoplastic resin could be lesscostly perhaps due to not requiring additives for UV stability such asTiO.sub.2 or due to loosened requirements for color uniformity orotherwise.

In addition to the various extruders discussed above, appropriatecalibrators, pullers and saws are needed for the production of the abovedescribed inventive extrusions and method. Additionally, stressesimparted during the extrusion calibration process may affect theapparent color of the pigment systems of the preferred embodimentsincluding the dark-colored capstock layer. Thus, the present inventionalso embodies a means to eliminate those stresses, and therefore providea consistent visual color, by applying heat after the product exits theextruder calibrator.

Tailoring the heat build-up performance of an extrusion is conducted byessentially three means. First, the thickness of the dark-coloredcapstock is manipulated to minimize IR absorbance as NIR initiallypasses through the dark-colored capstock and as it is reflected off ofthe substrate back through the dark-colored capstock. This manipulationmust also be done in a manner that preserves the visual color of thecapstock. Second, the substrate is manipulated to provide the requisiteIR reflectance, most commonly by manipulating the loading of TiO2 butalso with consideration of other substrate constituents. Third, thepigments in the dark-colored capstock required to impart particularcolors should be optimized to minimize their absorbance of NIR. Inpractice, all three means must be optimized for a particularcapstock/color/substrate combination to yield a functional finalproduct.

A preferred and useful pigment and cap material combination for the darkcolored capstock material is available from Lanier Color Company and canbe shown to posses the IR and weatherability properties desired, namelythat the pigment system is substantially transmissive of NIR and such apigment system is used in the inventive examples discussed, hereinbelow.The body of the dark colored capstock is Kaneka Corporation'sproprietary XM20, which is an extrusion grade acrylic. This acrylic hasa melt index value between approximately 13 g/10 min. and 20 g/10 min.as tested using ASTM D1238 standard at 230 degrees Celsius and 3.8 kgmass. This useful Lanier pigment system uses a black base pigment thatprovides a suitable base to which other pigments can be added to achievea desired particular color or chroma (e.g., forest green or bronze) asis well understood by color houses and those of ordinary skill in theart. Individual pigments may be reflective or transmissive of NIR solong as, overall, the pigment system is substantially NIR transmissive.The preferred Lanier pigment system, or a substitute that issubstantially NIR transparent, would be suitable for use in the presentinvention and would achieve the ends of the present invention. The darkcolored capstock may be solid colors or may be formed into wood grainsor other finishes with textured appearances. Further, touch-up paintsthat are substantially NIR transparent based on similar NIR transmissivepigment systems may be used to repair minor scratches or gaps in thedark colored capstock such as may occur at the corner welds in a windowframe.

The inventor believes that PVC lineals currently used in residentialwindow frames would likely be a suitable structural extrusion for thisinvention. A suitable formulation for the integrated insulation is shownin Table 1, below.

TABLE 1 Parts Per Hundred Resin Ingredient Supplier (by weight) PVCResin SE-650 - Shintech 100.0 Tin Butyl Stabilizer RT4458 - Reagens 1.2Ester Base Lubricant SA 0817B - Strucktol 1.5 Acrylic Modifier PA 40 -Kaneka 20.0 CaCO3 Filler Optifil JS - JM Huber 6.0 CBA Pigment 473LD -KibbeChem 5.0 Total Parts 133.7To this formulation, a person of ordinary skill in the art wouldtypically add a suitable blowing agent in an amount sufficient toachieve a density preferably below 0.4 g/cc and more preferably between0.2 and 0.4 g/cc. The amounts and type of blowing agent is determined bythe extrusion equipment used, the process conditions, and the particularshape and details of a particular extrusion as is well understood bythose of ordinary skill in the art. The inventor has in the past usedColor Matrix “Foamazol F-92” product as a blowing agent.

FIG. 1 illustrates an extrusion line 10 suitable for practicing theinventive process. An extrusion line suitable for use in an embodimentof the inventive process is disclosed in The extrusion line 10 consistsof at least two extruders including primary extruder 20 (first extruder)that includes a feed hopper 12 that drops into a feed column 14 whichfurther connects to a pre-mixer 16. Port 18 also feeds into feed column14 for the addition of micro ingredients such as a blowing agent.Alternatively, such micro ingredients can be added at hopper 19 directlyinto the premixer 16. The ingredients that reach premixer 16 are feddirectly into the mouth of primary extruder 20. A integrated insulationextruder (second extruder) and, in a preferred embodiment a dark coloredcapstock extruder (third extruder), and in a still further embodiment analternative structural extrusion extruder (fourth extruder) havingessentially these same features as described above for the primaryextruder are further disclosed.

A multi-plate extrusion die 22 is further described below with referenceFIG. 2, but multi-plate extrusion die 22 is operatively attached to theprimary extruder 20 the output of the primary extruder 20. The extrusionis shown at reference numeral 24 after it has exited multi-plateextrusion die 22. Extrusion 24 then enters calibrator 26 which is of theordinary type used in plastic profile extrusion and which includes sizerplates which form extrusion 24 into its final form and spray nozzles tocool and solidify extrusion 24.

After extrusion 24 exits calibrator 26, it enters heat treatment tube28. Heat treatment tube 28 may be formed of PVC pipe approximately threefeet long and of a diameter to allow easy clearance for extrusion 24 topass through it. Preferably, at the entrance and exits of heat treatmenttube 28, leister heaters 30 blow hot air into the tube and overextrusion 24. Alternatively, the heat treatment tube 28 can also beserved by an IR heating tube to heat the exterior surface of extrusion24. Further, the leister heaters 30 could be replaced with heat guns, IRheaters, radiant heaters or other devices that would heat the interiorof the heat treatment tube 28 and thereby heat the surface of extrusion24. The heat treatment tube 28 could be replaced with just Liester®heaters 30 or their substitutes that were noted above should bow ofextrusion 24 not be a significant concern. It should be understood thatheat treatment tube 28 is used only as necessary to correct for bow orto correct for surface color issues as has been described below and,thus, may not always be used. Extrusion 24 then continues on to puller32 and saw 34 that are entirely conventional extrusion equipment long inuse in the art.

One purpose for the heat treatment tube 28 is to eliminate theoccurrence of “streaking” in the dark colored capstock where uponinspection, there will be streak of a differing shade in a linetraveling down the length of extrusion 24 and it should be understoodthat heat treatment tube 28 or its substitutes would not be neededshould there be no color streaking. This streaking is believed to becaused by stresses formed in the surface of the dark colored capstock bythe calibration and cooling process which of necessity causes thesurface of the dark colored capstock to contact the interior surface ofcalibrator 26 and causes the part to cool most quickly on the surfaceand, more gradually, for the interior portions of the extrusion to coolrelatively more slowly. This streaking most typically is of a red shade.This streaking can be easily removed by heat treatment of the surface ofdark colored capstock and the use of the heat treatment tube, asdescribed above, heats the entire surface of extrusion 24 thus avoidingcausing extrusion 24 to bend or bow as can be caused by heating only oneside of the extrusion such as by directly blowing hot air onto a surfaceof extrusion 24. Heating the surface of extrusion 24 to approximately145.degree. F. to 150.degree. F. will remove the color streakingobserved in the dark colored cap disclosed herein and has found thatLeister heaters 30 blowing air at approximately 225.degree. F. into thetube has raised the surface of examples of extrusion 24 to the desired145.degree. F. to 150.degree. F.

FIG. 2 is an exploded view of the downstream sides of the individualplates of the multi-plate extrusion die 22 for use in a preferredembodiment of the inventive method. FIG. 2 illustrates a multi-plate dieassembly 22 shown in exploded form consisting of individual die plates36, 38, 40, and 42 and various intermediate plates connecting the samefor manufacturing the inventive extrudate. The manner of use of suchdies is well known to those of ordinary skill in the thermoplasticextrusion art. Nevertheless, it is sufficient to state that themulti-plate die assembly 22 shown in FIG. 2 is intended for use with aplurality of conventional extruders, such as conventional twin screwextruders, each of which includes a mixer or hopper for accepting athermoplastic resin feed stock, a conduit for connecting the hopper witha preheater for controlling the temperature of an admixture of the feedstock in the hopper, in the case of the second thermoplastic resin usedfor the integrated insulation, optionally an inlet for introducingfoaming agents for a foamed component. The multi-screw chamber of eachextruder is connected to an appropriate input on the die assembly platesshown in FIG. 2 for producing an embodiment of the extrudate withintegrated insulation.

As best seen in FIG. 2, one of the hereinabove described extruders (notshown) is fluidly connected to an introductory plate 36 for introductionof a first thermoplastic resin for forming the structural extrudatethrough the multi-plate die assembly 22. FIGS. 3, 4, 5, and 6 show theflow of the first thermoplastic resin for forming the structuralextrudate and the flow of the second thermoplastic resin forming theintegrated insulation as practiced with a hollow, thin-walled PVCextrudate.

Flow at approximately the midpoint within plate 38 of the multi-platedie assembly 22 is shown at FIG. 3. Inlet 44 for introducing the secondthermoplastic resin suitable for integrated insulation 46, a suitableformulation for such shown in Table 1, from the output of secondextruder and the inlet 48 for the first thermoplastic resin for thestructural extrusion 50, 52 is shown in FIGS. 2 and 3. As was describedabove, portions of the structural extrusion may consist of a fourththermoplastic resin of lower cost and could be fed through to 50 in thisexemplary extrusion from a fourth extruder from an un-shown inlet in asimilar manner to inlet 44. The portions of the structural extrusion at52, or all of the structural extrusion 50, 52, are fed through inlet 48of the multi-plate die assembly 22 from the output of the firstextruder. The multiple channels flowing the structural extrusion 50, 52are shaped to help equalize the flow and to allow the insertion of theintegrated insulation 46 within the interior of structural extrusion 50,52.

Flow at approximately the midpoint within plate 40 of the multi-platedie assembly 22 (shown in FIG. 2) is shown at FIG. 4. The structuralextrusion 50, 52 is much closer to shape of its intended final form. Theintended integrated insulation 46 can be seen in the interior ofstructural extrusion 50, 52.

The entrance to plate 42 of the multi-plate die assembly 22 (shown inFIG. 2) is shown at FIG. 5 for the preferred embodiment of integratedinsulation 46. The exit of plate 42 of the multi-plate die assembly 22(shown in FIG. 2) is shown at FIG. 6 for the preferred embodiment ofintegrated insulation 46. The typical preferred final shape of thepreferred embodiment of integrated insulation 46 is shown in twodifferent window component extrusions at FIGS. 9 and 10. The integratedinsulation 46 is broken up into a group of “ribbons” or “strands”beginning at the entrance to plate 42 shown at FIG. 5. At the exit toplate 42, shown at FIG. 6, integrated insulation 46 is twenty-twoindividual stands of the second thermoplastic resin. Note that theintegrated insulation may easily be left out of the extrusion to savecosts, where such performance is not needed, merely by not adding thesecond extruder. This allows the option of a less costly extrusionwithout integrated insulation without adding further die or toolingcosts.

In this preferred embodiment, the individual stands of the integratedinsulation 46 expand due to the blowing agent and due to the lowerpressure at the exit of multi-plate die assembly 22 at plate 42, bestseen in FIG. 6. In the preferred embodiment, the individual stands ofthe integrated insulation 46 expand until they crowd together and meshtogether where they meet while leaving a series of air pockets 54running the length of the extrudate with integrated foam insulation. Ifthe flow of the integrated insulation 46 is too high or the foam is tooaggressive, then the strands will push tightly together leaving no airpockets.

FIG. 7 shows cut-away partial side views of the possible interior viewsof plate 42 of the multi-plate die assembly 22. The entrance side isshown on the left at 56 and the exit shown at 58 showing the flow of anindividual strand of integrated insulation 46 through plate 42 where thesize of the exit orifice is preferably between 0.08 and 0.10 inchesshown at 60 and where the orifices are typically spaced between 0.08 and0.10 inches apart and from a wall of the structural extrusion 50, 52.The left-hand version shown is typically referred to as “free-foam”version allowing the maximum flow of an individual strand of theintegrated insulation 46. The right hand version has a die land 62 whichis a parallel portion of walls of the die. Such a die land 62 will serveto increase the drag on the individual strand of the integratedinsulation 46 reducing the flow rate through plate 42. By shortening thedie land 62, one can increase the flow of an individual strand of theintegrated insulation 46 allowing “tuning” of the multi-plate dieassembly 22 to allow the formation and retention of the air pockets 54seen in FIGS. 9 and 10.

Inventor has found that individual strands of the integrated insulation46 that exit plate 42 of the multi-plate die assembly 22 throughorifices between 0.08 and 0.10 inches and spaced between 0.08 and 0.10inches apart typically need a die land of 0.05 to 0.2 inches. The angleof the orifice prior to the die land has not been found to be critical.

FIG. 8 shows two alternate embodiments of possible integrated insulation46. Instead of extruding individual strands that partially mergetogether leaving air pockets, here, the orifices in the die plate wouldbe narrow slots. These slots can be arranged to allow multiple airpockets and low overall density of the integrated insulation 46.

The structural extrusion 50, 52 and the integrated insulation can beeasily recycled by grinding up the extrusions as with a standard, hollowPVC extrusion, while using an aspirator on the ground materials tosubstantially remove the substantially lower density integratedinsulation. The recycled and substantially uniform structural extrusionmaterials can then be reused in the extrusion process.

The integrated insulation 46 of the inventive process and extrudatesubstantially match or exceed commercially available polyethylene andpolyurethane insulation products. As such, the windows made with theinventive extrudate and triple pane glass packs have tested to a 0.15U-factor/R6.5 window substantially exceeding current EnergyStar®requirements of a 0.3 U-factor. The manufacturing of the inventiveextrudate into a completed window does not require any additional orchanged fabrication steps from standard hollow PVC window, whileoffering substantially better performance.

1. A window for use in a residential or commercial structure,comprising: a glass pack operatively installed in a window frame, wherethe window frame further comprises: a structural extrusion formed of afirst thermoplastic resin suitable for use in the fenestration industryand which contains at least one hollow interior portion and which is ofa constant profile and extends to an indefinite length, an integratedinsulation formed of a second thermoplastic resin substantially fillingat least one hollow portion of the structural extrusion, where the firstthermoplastic resin and the second thermoplastic resin are compatibleand recyclable together and where the structural extrusion and theintegrated insulation are coextruded through an extrusion die.
 2. Thewindow for use in a residential or commercial structure of claim 1,wherein, the second thermoplastic resin of the integrated insulation isfoamed and further contains a plurality of air pockets running in thelength of the extrudate.
 3. The window for use in a residential orcommercial structure of claim 2, wherein the thermoplastic resin and thesecond thermoplastic resin are comprised of polyvinyl chloride (PVC)resin.
 4. The window for use in a residential or commercial structure ofclaim 3, further comprising a dark-colored capstock portion that isformed of a third thermoplastic resin that is significantly transmissiveof solar infrared radiation and that covers at least a portion of thestructural extrusion and where the dark-colored capstock is less thanabout 10 thousandths of an inch thick and the first thermoplastic resincontains between 8 and 11 parts titanium dioxide per hundred base resin.5. The window for use in a residential or commercial structure of claim4, wherein the dark-colored capstock is between about 4 thousandths andabout 8 thousandths of an inch thick and the first thermoplastic resincontains between 8 and 11 parts titanium dioxide per hundred base resin.6. A method of producing an extrudate with integral foam insulation,comprising the steps of: feeding a first thermoplastic resin suitablefor use in a structural component in the fenestration industry into afirst extruder; feeding a second thermoplastic resin suitable forintegrated insulation into a second extruder; outputting the first andsecond extruders to an extrusion die extruding the extrudate, where theextrusion die forms the structural extrusion formed of the firstthermoplastic resin, suitable for use in the fenestration industry,containing at least one hollow interior portion, of a constant profile,and extending to an indefinite length, and, substantially fills thehollow portion of the structural extrusion with an integrated insulationformed of a second thermoplastic resin.
 7. The method of claim 6 whereinthe second thermoplastic resin of the integrated insulation is foamedand further contains a plurality of air pockets running in the length ofthe extrudate.
 8. The method of claim 7, wherein the plurality of airpockets of the integrated insulation running in the length of theextrudate are formed by the extrusion die with a plurality of individualoutlets having a die land between 0.05 and 0.2 inches.
 9. The method ofclaim 8, further comprising feeding a third thermoplastic resin that issignificantly transmissive of solar infrared radiation into a thirdextruder and outputting the third extruder into the extrusion die sothat the third thermoplastic resin forms a dark-colored capstock layerof less than about 10 thousandths of an inch thick on a surface of thestructural extrusion formed of the first thermoplastic resin.
 10. Themethod of claim 9, wherein the extrusion die forms the dark-coloredcapstock portion into a layer less than about 8 thousandths of an inchthick and the first thermoplastic resin contains between about 8 and 11parts titanium dioxide per hundred base resin.
 11. A method of producingan extrudate with integral foam insulation, comprising the steps of:extruding a first thermoplastic resin to define a structure suitable foruse in the fenestration industry; the structure having a longitudinaldirection; extruding a second thermoplastic resin in the form of aplurality of foamed strands disposed within the structure to define aplurality of longitudinal air pockets disposed within the structure;bonding at least some of the foamed strands to the structure to form anintegral insulated structure.
 12. The method of claim 11, furthercomprising the step of selecting the first thermoplastic resin and thesecond thermoplastic resin to be recyclable together.
 13. The method ofclaim 12, further comprising the step of selecting the firstthermoplastic resin and the second thermoplastic resin to be resinscomprised of polyvinyl chloride.
 14. The method of claim 11, furthercomprising the step of extruding the first and second resins from thesame extrusion die.
 15. The method of claim 11, further comprising thestep of forming the structure with a structural perimeter wall thatdefines first and second separated chambers disposed in the longitudinaldirection.
 16. The method of claim 14, further comprising the stepextruding the second thermoplastic resin in the form of a plurality offoamed strands within the second chamber to define a plurality oflongitudinal air pockets disposed within the second chamber.
 17. Themethod of claim 11, further comprising the step of forming the strandsand air pockets with an extrusion die having a plurality of outletshaving a die land between 0.05 and 0.2 inches.